P2112

Symptoms

• Check engine light and/or throttle warning lamp
• unresponsive throttle
• loss of power and sluggish acceleration
• limp-mode operation
• poor fuel economy
• vehicle may start (enough idle air passes the closed plate) but be unable to accelerate
• in some cases the vehicle fails to start.

Probable causes

• 1) Throttle body assembly or actuator motor failure — shorted coil
• open circuit or failed motor driver preventing the actuator from opening the plate. 2) Carbon buildup
• grease or debris causing the plate to stick closed. 3) Wiring faults — corroded pins
• broken wires
• loose connectors between the ECM/PCM and the actuator disrupting command or feedback signals. 4) PCM/ECM problems — corrupted software or a failing module sending an incorrect closed command or misreading actuator feedback (false P2112).

Diagnostic steps

1. Scan codes and freeze frame; confirm P2112 and any accompanying TPS/APP codes.
2. Inspect the throttle body and actuator for physical damage, corrosion, carbon buildup or debris preventing the plate from opening; clean the throttle body if fouled.
3. Inspect wiring and connectors in the throttle actuator circuit for loose connections, broken wires or corroded pins.
4. With a scan tool, monitor the throttle position sensor reading, the commanded throttle angle and the actual actuator position while pressing the pedal — a large discrepancy between commanded and actual position indicates a stuck actuator.
5. Verify the actuator receives supply voltage with the ignition on.
6. Replace the throttle body/actuator if it fails these tests; if wiring and actuator check good, evaluate the PCM (software update or module diagnosis).
7. Clear codes and road test to confirm normal throttle response.